Flame retardant plastics and additives are a 2.2 billion dollar market. Flame retardant plastics and additives are used in electronic devices, mattresses and cushions, and fabrics, including fabrics used in pajamas, blankets, and tents (Chemical and Engineering News, Dec. 4, 2000, Vol. 78, No. 49, pp. 21-31).
Heat stabilizers, primarily used in polyvinylchloride pipes, are a 1.8 billion dollar market. Lead and mixed metals such as cadmium/zinc are the most common heat stabilizers. But these have the disadvantage that lead and some other metals are known to carry health risks (Id.).
The most commonly used flame retardants are bromine-, chlorine-, or antimony-containing compounds. An example is brominated polystyrene. Brominated polystyrene is added to polystyrene at an appropriate level to create flame retardant properties. The addition of brominated polystyrene, however, degrades the physical properties of the polystyrene. Halogenated polymers also pose environmental problems. They are believed to release polybrominated dioxins and polybrominated dibenzofurans when incinerated (Id.). Other typical flame retardant additives include halogenated biphenyls, antimony oxide, ammonium polyphosphate, inorganic hydroxides, and organophosphates.
Polybenzoxazoles (PBOs) are one type of flame retardant polymer. Polybenzoxazoles are quite rigid and form a char in heat. The char can seal and protect other flammable materials from fire or heat. (So, Y. H. 2000. Prog. Polym. Sci. 25:137.)
Polyhydroxyamides (PHAs) are polymers that cyclize in heat to form PBOs. (Yoo, E.-S. et al. 2003. High Performance Polymers 15:519.)
New flame-retardant and heat-stable polymer compositions are needed. Preferably the polymer compositions can retain the range of properties available in polymers that are flammable and heat labile.